Conventional X-ray CT apparatuses have a function of specifying a position to which a bed is moved along the body axis direction on a reference image (scanogram, scanning image etc.) displayed on a display. The scanogram is an image obtained for determining a position of a subject at the time of main imaging, and the scanning image is a CT image obtained in the main imaging.
In recent years, there is proposed a method of moving a bed for placing a subject along the transverse direction (body width direction) or the height direction (body thickness direction), in addition to the body axis direction. If a site to be imaged is placed at the revolution center of the gantry by moving the bed along the transverse direction or height direction, improvement of spatial resolution of CT images can be expected.
Patent document 1: Japanese Patent Unexamined Publication No. 2007-267783
Patent document 2: Japanese Patent Unexamined Publication No. 2010-57731
Patent document 3: Japanese Patent Unexamined Publication No. 2010-187812
For example, Patent document 1 proposes a mechanism for setting an imaging region at an objective site on a scanogram, and moving a bed to the center position of the region. In the mechanism described in Patent document 1, a bow tie filter is automatically set in order to reduce dose of regions other than the imaging region. However, in Patent document 1, whether the bed can be safely moved, that is, whether the subject may not contact with a gantry when the bed is moved, is not taken into consideration.
Therefore, Patent document 2 proposes a mechanism for setting a movement destination by using a marker, and proposes a setting using not only a scanogram, but also a scanning image, as the reference image.
Moreover, Patent document 3 proposes a mechanism for providing guide display of a region in which a bed can be safely moved.